The present invention relates to a method of and a circuit arrangement for driving a mechanical two coordinate oscillator with the aid of a deformed rotating field of forces defined by a plurality of exciting and pick-up components.
From the German Patent Specification No. 1,213,141 it is known that tumbler mirrors consist of a mirror mounted obliquely to a rotating shaft. They are used in the optical measuring technology for the production of an oscillation in two coordinate directions. Such arrangements, apart from the fact that the rotating parts are subject to certain wear and tear, also are subject to a bearing play leading to angle errors, which latter appear with double their value in the reflected beam. It is further known to set a system capable of oscillating in two mutually perpendicular coordinates into oscillation by causing the system to be excited into self-resonance in respect of one coordinate. Further signals, which correspond according to amplitude and phase to the nominal signals of the other directional components and which combine together to define a circular oscillation, are derived from this self-oscillation by phase shifting and potential dividing. The maintenance of an amplitude of the self-oscillation fed in as proportional nominal value voltage is supervised by additional regulating devices and, by comparison of the derived nominal signals with the measured actual values of the other directional components, control signals are obtained, by which the system is excited in respect to these exciting and pick-up components to forced oscillation at the frequency of the one self-oscillation.
This "master-slave" circuit has the disadvantage that in case of somewhat larger deviations of the natural frequency of the individual direction components from the natural frequency of the "master" oscillator, the power dissipation of the forced oscillation becomes disproportionally much greater than that of the self-oscillation. This has a particularly disadvantageous effect when the oscillator must take its drive energy from solar cells or batteries.